Flowmeters which make use of the widest possible range of flow-dependent measuring effects are known and widely used. They differ in structural shape, which is dependent on the measuring effect on which they are based. Often, so-called Coriolis meters are used, in which the measuring medium is passed through a bent measuring tube, which causes deflection as a function of the flow, which is then measured, the flow being calculated therefrom and indicated.
This structural shape also entails that deflection of the measuring tube remain limited to the selected measuring path. Since vibrations are generated by the deflection, this vibration needs to remain vibrationally or mechanically isolated to the length of the measuring path without dissipating energy outwards.
However, these connections between the measuring tube and the housing are also subject to the effects of changing temperatures. The measuring tube has always to remain firmly clamped in place, since deflection is ultimately the variable which is of relevance to flow. Therefore all other forms of mechanical mobility have to be eliminated, so as not to distort the measuring effect. This includes avoiding mechanical play development due to thermal factors.
A connection of this type is known from US 2003/0084559A1, in which a shrink-mounting method is selected, i.e. the materials are dimensioned relative to one another so as to produce a shrink-fit, i.e. the material is thermally expanded and then shrunk onto the corresponding component by cooling.
If welded or brazed connections are to be put to only certain uses, special requirements have to be made of any form of shrunk or clamped connection.
One problem is that clamped or shrunk connections must not loosen in particular under the effects of temperature changes. Apart from the fact that the entire static design would thereby be called into question, the mechanical play arising would be added to the tube deflection caused by the measuring effect and would thus distort the measured value to an enormous degree.